Scrutinizing the double superconducting gaps and strong coupling pairing in (Li(1-x)Fe(x))OHFeSe
| Autor: | Xiyu Zhu, Hai-Hu Wen, Delong Fang, Jie Xing, Xiong Yang, Guan Du, Huan Yang, Hai Lin, Zengyi Du |
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| Rok vydání: | 2015 |
| Předmět: |
Science
FOS: Physical sciences General Physics and Astronomy Nanotechnology 02 engineering and technology 01 natural sciences General Biochemistry Genetics and Molecular Biology Article Superconductivity (cond-mat.supr-con) Atomic orbital Condensed Matter::Superconductivity 0103 physical sciences Monolayer Thin film 010306 general physics Quantum tunnelling Superconductivity Physics Multidisciplinary Condensed matter physics Condensed Matter - Superconductivity Transition temperature General Chemistry 021001 nanoscience & nanotechnology Pairing Quasiparticle 0210 nano-technology |
| Zdroj: | Nature Communications Nature Communications, Vol 7, Iss 1, Pp 1-8 (2016) |
| ISSN: | 2041-1723 |
| Popis: | In the iron based superconductors, one of the on-going frontier studies is about the pairing mechanism. The recent interest concerns the high temperature superconductivity and its intimate reason in the monolayer FeSe thin films. The challenge here is how the double superconducting gaps seen by the scanning tunnelling spectroscopy (STS) associate however to only one set of Fermi pockets seen by the angle resolved photoemission spectroscopy (ARPES). The recently discovered (Li1-xFexOH)FeSe phase with Tc=40 K provides a good platform to check the fundamental problems. Here we report the STS study on the (Li1-xFexOH)FeSe single crystals. The STS spectrum clearly indicates the presence of double anisotropic gaps with maximum magnitudes of Delta_1=14.3 meV and Delta_2=8.6 meV, and mimics that of the monolayer FeSe thin film. Further analysis based on the quasiparticle interference (QPI) allows us to rule out the d-wave gap, and for the first time assign the larger (smaller) gap to the outer (inner) hybridized Fermi pockets associating with the dxy (dxz/dyz) orbitals, respectively. The huge value Delta_1/k_BT_c = 8.7 discovered here undoubtedly proves the strong coupling mechanism in the present superconducting system. 24 pages, 10 figures, with the Supplementary Information. The second version supersedes the original version with detailed QPI data and analysis |
| Databáze: | OpenAIRE |
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